Esters of polyphenolic compounds as built-in antioxidants

ABSTRACT

This invention concerns a method for the preparation of polyphenolic esters for use as built-in antioxidants.

This is a Division of application Ser. No. 467,426 filed May 6, 1974,nowabandoned.

This invention relates to new polyphenolic type antioxidants, to amethod of preparing the materials and to polymer compositions concerningthese materials.

The prior art teaches that antioxidant activity in phenolic compoundsoccurs because of hydrogen abstraction from the hydroxyl groups [Scott"Atmospheric Oxidation and Antioxidants" Chapter IV, 1965]. It has beenfound according to the present invention that by partial esterificationof a polyphenolic compound, both antioxidant activity and nonstainingcharacteristics can be enhanced. This is a surprising result since itappears to contradict the prior art theory on how phenolic antioxidantsperform.

It is an object of the present invention to provide new polymerizablephenolic ester antioxidants and a process for their manufacture. Furtherobjects will be evident to those skilled in this art as the descriptionproceeds.

The antioxidants of this invention are partial esters of polyphenols.The term "partial esters" is used to mean esterified polyphenols inwhich less than all of the phenolic hydroxyl groups of the phenol areesterified.

The above compounds are prepared by reacting (A) polyphenolic compoundscontaining two or more aromatic rings which each contain phenolichydroxyl groups with (B) acid halides or other similar derivativescapable of forming unsaturated polymerizable esters. The polyphenolicstarting materials may be initially prepared by methods well known tothose skilled in this art or it may be a commercially availablepolyphenolic. A description of the preparation of some of thesepolyphenolic compounds can be found in U.S. Pat. Nos. 3,036,138 and3,305,522.

Polyphenolic compounds which can be used to prepare the antioxidants ofthis invention have the structural formula ##STR1## wherein R¹ and R²are different radicals selected from the group consisting of hydrogenand alkyl radicals containing from 1 to 16 carbon atoms, cycloalkylradicals containing from 5 to 9 carbon atoms, aralkyl radicalscontaining from 7 to 12 carbon atoms, and substituted and unsubstitutedaryl radicals having from 6 to 12 carbon atoms and R¹ preferablycontains from 1 to 2 carbon atoms when para to the hydroxyl group, X isthe same or different radical selected from the group consisting of (1)cyclic dienes with non-adjacent carbon to carbon double bonds within thering structure containing from 5 to 20 carbon atoms from which thedivalent radicals are prepared and (2) a bivalent radical selected fromthe group consisting of --S--, --O--, --C═O, --CH₂ --, --S--S-- andwherein n is selected from the group consisting of 0 and real numbersfrom 1 to 5.

The polyphenolic is reacted with a compound capable of forming an esterhaving the general formula ##STR2## wherein R³ is selected from thegroup consisting of hydrogen and alkyl radicals having from 1 to 4carbon atoms, R⁴ is selected from the group consisting of hydrogen,alkyl radicals having from 1 to 4 carbon atoms, aralkyl radicals havingfrom 7 to 12 carbon atoms, cycloalkyl radicals having from 5 to 8 carbonatoms and substituted or unsubstituted aryl radicals having from 6 to 12carbon atoms, and wherein A is selected from the group consisting ofchlorine, bromine and iodine. The amount of esterification of coursedepends on the molar ratios and steric hindrance of the materials used.Preferably the polyphenolic material is treated with from one mole to0.1 mole of ester forming compound for each functional hydroxyl group.More preferably at least one functional hydroxyl group per polyphenolicmolecule is esterified.

When the polyphenolics and ester forming compounds described herein arereacted in a 1:1 molar ratio, a near theoretical reaction takes place.Compounds having the formula (A) wherein n is 0 and X is a divalentradical selected from the group consisting of --S--, --CH₂ --, and R² isa hydrocarbon radical of at least 4 carbon atoms (preferably tertiary)and ortho to the hydroxyl group, have only one readily reactive hydroxylgroup. Upon esterification of one hydroxyl group, steric hindranceoperates to decrease the reaction at the second hydroxyl site. Forexample, if one mole of methacryloyl chloride is reacted with one moleof 2,2'-methylene-bis-(4-methyl-6-tert.butylphenol) a near theoreticalamount of 2-(2-hydroxy-3-tert.butyl-5-methylbenzyl)-4-methylphenylmethacrylate is obtained.

When a polyphenolic according to structure (A) wherein R² (preferablytertiary) is ortho to the hydroxyl group and is reacted with n+2 molesof an ester forming compound having structure (B), less than n+2 molesof compound (B) will react. Normally the number of ester groups reactingwith the polyphenolic reactant is not more than n+1.5 or less thann-0.75. when n is 0 the number of ester groups reacting with thepolyphenolic is usually not more than 1.5 or less than 0.25.

The esterification reaction may easily take place at elevated pressureand temperatures from 0° to the boiling point of the reactants.Preferably temperatures from 0° to 60° C. are preferred.

Representative examples of the radicals of the above formulas are alkylradicals such as methyl, ethyl, butyl, pentyl, hexyl and decyl;cycloalkyl radicals such as cyclopentyl, cyclohexyl; alkylaryl radicalssuch as methylphenyl and decylphenyl; aryl radicals such as phenyl andnaphthyl; aralkyl radicals such as benzyl and 4-methylbenzyl; andhalogens such as bromo, iodo and chloro.

The above compounds are prepared by reacting conventional antioxidantcompounds comprising polyphenolic compounds having 2 or more aromaticrings containing phenolic hydroxyl groups with compounds such asacryloyl chloride or other similar derivatives capable of formingunsaturated polymerizable esters. Some of the polyphenolic startingmaterials can be initially prepared by methods well known to thoseskilled in this art such as those taught in U.S. Pat. Nos. 3,305,522 and3,036,138. The phenolic esters of this invention may be chemicallybonded or "built" onto polymer chains. Such built-in antioxidants cannot be lost due to volatility or extraction.

Representative examples of cyclic dienes useful in this invention are1,5-cyclooctadiene, cyclopentadiene, bicyclo[2.2.1]-2,5-heptadiene,2-methyl bicyclo[2.2.1]-2,5-heptadiene, dicyclopentadiene,pentacyclo[8.2.1.1⁴.spsp.9⁷.0².spsp.9⁹.0³.spsp.9.sup.8]-tetradeca-5,11-diene, and 1,5,9-cyclodedecadiene.

Representative examples of phenolic compounds useful in the practice ofthis invention include2,6-bis-(2-hydroxy-3-tert.butyl-5-methylbenzyl)-4-methylphenol;2,2'-methylene-bis-(4-methyl-6-tert.butylphenol);2,2'-methylene-bis-(4-ethyl-6-tert.butylphenol); and2,6-bis-(2-hydroxy-3-tert.butyl-5-ethylbenzyl)-4-ethylphenol, andcompounds similar to those prepared in U.S. Pat. Nos. 3,625,874;3,036,138 and 3,305,522.

Representative examples of ester forming compounds that can be used inthe practice of this invention include acryloyl chloride, methacryloylchloride, crotonyl chloride, cinnamoyl chloride, acryloyl bromide,ethacryloyl chloride, β-cyclohexyl acryloyl chloride andβ-(4-methylcyclohexyl)acryloyl chloride.

Representative examples of compounds produced by the process of thepresent invention are listed below.

2-(2-hydroxy-3-tert.butyl-5-methylbenzyl)-4-methyl-6-tert.butylphenylacrylate

2-(2-hydroxy-3-tert.butyl-5-methylbenzyl)-4-methyl-6-tert.butylphenylmethacrylate

2,6-bis(2-hydroxy-3-tert.butyl-5-methylbenzyl)-4-methylphenylmethacrylate

and the reaction products of Examples 3 through 7, 9 and 10.

The polyphenolic compounds described in this invention can be reactedwith the ester forming compounds in a ratio as described above.Preferably at least one mole of ester forming compound is reacted withone mole of polyphenolic compound.

The polymers that may be conveniently protected by the compoundsdescribed herein are vulcanized and unvulcanized polymers susceptible tooxygen degradation, such as natural rubber, balata, gutta percha andrubbery synthetic polymers containing carbon to carbon double bonds.Representative examples of the synthetic polymers used in the practiceof this invention are polychloroprene; homopolymers of a conjugated1,3-diene such as isoprene and butadiene with up to 40 percent by weightof at least one copolymerizable monomer such as styrene andacrylonitrile; butyl rubber, which is a polymerization product of amajor proportion of a monoolefin and a minor proportion of a multiolefinsuch as butadiene or isoprene; polyurethanes containing carbon to carbondouble bonds; and polymers and copolymers of monoolefins containinglittle or no unsaturation, such as polyethylene, polypropylene, ethylenepropylene copolymers and terpolymers of ethylene, propylene and anonconjugated diene. When added in free form normally 0.001 to 10.0percent of the antioxidant by weight based on the weight of the polymercan be used, although the precise amount of the age resisters which isto be employed will depend somewhat on the nature of the polymer and theseverity of the deteriorating conditions to which the polymer is to beexposed. In unsaturated polymers such as those made from conjugateddienes, the amount of age resister necessary is greater than thatrequired by a saturated polymer such as polyethylene. It has been foundthat an effective antioxidant amount of the disclosed stabilizers inrubbery unsaturated polymers will generally range from 0.05 to 5.0percent by weight based on the weight of the polymer although it iscommonly preferred to use from 0.5 to 3.0 percent by weight based on theweight of the polymer. Mixtures of the age resisters may be used. Thesepolymers, whether liquid or solid, have a special advantage in that theantioxidant portion is not extractable, and therefore the polymericcompositions are highly resistant to oxidative aging even after repeatedexposure to aqueous detergent solutions or drycleaning fluids. Thisfeature is especially significant where polymers are used in foambackings for rugs and where polymers are used in solution or latex formto treat fabrics, since such products are often exposed to aqueousdetergent solutions or drycleaning fluids.

A polymer composition will usually contain other compounding materialssuch as additives and reinforcing materials used with vulcanized rubberproducts. Representative examples of such additives are metal oxides,reinforcing agents, pigments, fillers, softening agents, otherantioxidants, plasticizing agents, curing agents and the like.

The examples below illustrate typical runs made to produce thepolyphenolic ester antioxidant. All parts and percentages are by weightunless otherwise indicated.

EXAMPLE 1

Three hundred and twenty-four grams of p-cresol and 5.3 grams of BF₃etherate were added to a flask equipped with a water condenser, stirrer,thermometer and heated to 90° C. One hundred thirty-two grams ofdicyclopentadiene were added over a twenty minute period. Five grams oflime were then added and the reaction product was heated to a reactortemperature of 195° C. at 20 millimeters of mercury. Three hundred gramsof toluene were added and the product was filtered. The toluene wasremoved from the product at a reaction temperature of 180° C. undervacuum. The reaction product had a weight of 300 grams.

EXAMPLE 2

One hundred grams of the polyphenolic product prepared in Example 1 and10 grams of toluene sulfonic acid were dissolved in 100 milliliters oftoluene between 60° C. and 70° C. Isobutylene was added until no morewould react. The reaction was neutralized with 10 grams of Na₂ CO₃ inaqueous solution, then decanted. The reaction product was heated to areactor temperature of 170° C. under vacuum to remove volatiles in thepresence of one gram of dry sodium carbonate. The reaction product had aweight of 122 grams.

EXAMPLE 3

One hundred grams of the butylated polyphenol prepared in Example 2, 8.9grams of triethylamine and 150 milliliters of tetrahydrofuran wereheated to 65° C. 4.4 Grams of methacryloyl chloride were added to thereaction product. The reaction product was stirred for 90 minutesbetween 65° C. and 70° C. and then filtered. The reaction product ofbutylated polyphenol/1/4 mole methacryloyl chloride was heated to areactor temperature of 165° C. at 25 millimeters of mercury to removethe volatiles.

EXAMPLE 4

This example was carried out in the same manner as Example 3 using 100grams of the butylated polyphenol prepared as described in Example 2.17.9 Grams of triethylamine and 8.8 grams of methacryloyl chloride wereused yielding the reaction product of one mole butylated polyphenol/1/2mole methacryloyl chloride.

EXAMPLE 5

Fifty grams of the product prepared as described in Example 2 weredissolved in 50 milliliters of tetrahydrofuran and 17.7 grams oftriethylamine at 70° C. 8.8 Grams of methacryloyl chloride were added.The mixture was stirred at 70° C. for 31/2 hours and then filtered. Thereaction product of one mole butylated polyphenol/one mole methacryloylchloride was heated to a reactor temperature of 160° C. at 15millimeters of mercury to remove volatiles.

EXAMPLE 6

This example was carried out in the same manner as Example 3 using 100grams of the butylated polyphenol prepared as described in Example 2.35.2 Grams of methacryloyl chloride and 71 grams of triethylamine wereused yielding the reaction product of one mole butylated polyphenol/2moles methacryloyl chloride. The reaction product had a weight of 128grams.

EXAMPLE 7

This example was carried out in the same manner as Example 3 using 100grams of the butylated polyphenol prepared as described in Example 2.107 Grams of triethylamine and 52.8 grams of methacryloyl chloride wereused yielding the reaction product of one mole butylated polyphenol/3moles methacryloyl chloride.

EXAMPLE 8

Nine hundred seventy-two grams of p-cresol and 16 grams of BF₃ etheratewere heated to 90° C. 396 Grams of dicyclopentadiene were added over a30 minute period. Seventy-five grams of triethyl phosphite and 15 gramsof calcium hydroxide were then added. The mixture was stirred at 95° C.for two hours and then the unreacted p-cresol was removed at a reactortemperature of 205° C. and 15 millimeters of mercury. The resin wasdiluted with 500 milliliters of toluene and filtered. The filtrate washeated to remove the toluene solvent yielding the product having aweight of 909 grams.

EXAMPLE 9

This example was carried out in the same manner as Example 3. Onehundred grams of the resin prepared in Example 8, 30 grams oftriethylamine and 20 grams of methacryloyl chloride were used. Thereaction product had a weight of 113.5 grams.

EXAMPLE 10

This example was carried out in the same manner as Example 3. Onehundred grams of the resin prepared in Example 8, 62.4 grams ofmethacryloyl chloride and 90 grams of triethylamine were used.

EXAMPLE 11

Forty-five grams of 2,2'-methylene-bis-(4-ethyl-6-t.butylphenol) and18.5 grams of triethylamine were dissolved in 100 milliliters oftetrahydrofuran. Fourteen grams of methacryloyl chloride were addedbelow 40° C. over a ten minute period. After stirring for thirtyminutes, the reaction product was washed with water. The volatiles wereremoved at a reactor temperature below 80° C. under vacuum. The productwas recrystallized from petroleum ether. The product had a melting pointof 86° C. to 87° C. and was characterized as2-(2-hydroxy-3-t.butyl-5-ethylbenzyl)-4-ethyl-6-t.butylphenylmethacrylate. The reaction product had a melting point of 86° C.to 87° C.

EXAMPLE 12

One hundred grams of 2,2'-methylene-bis-(4-methyl-6-t.butylphenol) and60 grams of triethylamine were dissolved in 150 milliliters oftetrahydrofuran. Thirty-one grams of methacryloyl chloride were addedover a ten minute period. The reaction product was stirred at 65° C. to75° C. for one hour and then filtered. The volatiles were removed undera vacuum. The product was recrystallized from petroleum ether yieldingnearly pure 2-(2-hydroxy-3-t.butyl-5-methylbenzyl)-4-methyl-6-tert.butyl phenylmethacrylate having a melting point between 141° C. and 142°C.

EXAMPLE 13

Seventy-five grams of 2,2'-thio-bis-(4-methyl-6-t.butylphenol) and 31grams of triethylamine were dissolved in 150 milliliters oftetrahydrofuran. Twenty-four grams of methacryloyl chloride were addedover a fifteen minute period at 30° C. The reaction product was stirredfor an additional fifty minutes and then washed four times with 150milliliter portions of water. The reaction product was diluted with 150milliliters of toluene and filtered. The volatiles were removed at areactor temperature below 80° C. under vacuum. The product wasrecrystallized from petroleum ether. The2-(2-hydroxy-3-t.butyl-5-methylphenylthio)-4-methyl-6-t.butylphenylmethacrylatehad a melting point between 171° C. and 172° C.

EXAMPLE 14

Forty-five grams of2,6-bis-(2-hydroxy-3-t.butyl-5-methylbenzyl)-4-methylphenol and 20 gramsof triethylamine were dissolved in 125 milliliters of tetrahydrofuran.Ten grams of methacryloyl chloride were added over a five minute period.The reaction product was stirred for 11/2 hours at 50° C. and thenwashed with water. The reaction product was filtered and heated to areactor temperature of 85° C. under vacuum to remove volatiles.

The aforementioned monomeric antioxidants may be polymerized by wellknown free radical emulsion polymerization techniques with one or morecomonomers that are known to polymerize in free radical initiatedpolymerization systems. Some adjustments in the polymerization recipeand/or conditions may be necessary to obtain a satisfactory rate ofpolymer formation, depending on the amount of monomeric antioxidantsincluded and the other monomers involved. Adjustments which may benecessary in the polymerization conditions to improve polymerizationrates include increasing the temperature of polymerization and/orincreasing the initiator level and/or increasing the level of activatoringredients. Solvents may also be required to obtain adequate solubilityof the monomers with each other as well as to solubilize otheringredients where required. Some solvents, such as methyl ethyl ketoneor isopropyl alcohol, can be used to advantage with the emulsionpolymerization system. These adjustments, where necessary, are tocounteract the inhibitory effect of the monomeric antioxidant and toinsure its solubility in the system.

Examples of free radical initiators that are useful in the practice ofthis invention are those known as "Redox" initiators, such asappropriate combinations of chelated iron salts, sodium formaldehydesulfoxylate and organic hydroperoxides such as cumene and paramenthanehydroperoxides. Other initiators such as azoisobutyronitrile, benzoylperoxide, hydrogen peroxide and potassium persulfate may also be used,depending on the particular polymerization recipe.

The monomeric antioxidants used in the practice of this invention havecertain chemical characteristics which preclude their use inpolymerization processes other than those initiated by free radicals. By"free radical initiated systems" is meant systems wherein free radicalsare generated by any of various processes such as thermal decompositionof various persulfate, perborate, peroxide, azo or azonitrile compounds;induced (catalytic or "redox" promoted) decomposition of variouspersulfate, peroxide or hydroperoxide compounds and generation of freeradicals by exposure of the system to high energy radiation such asradiation from a radioactive source of ultraviolet light. Such systemsare very well known in the art and are widely used commercially, e.g.,in the preparation of SBR, styrene/butadiene copolymers.

The most widely used system for preparation of elastomeric polymers,i.e., polymers prepared from a monomer charge made up of at least 40weight percent diene, preferably at least 60 weight percent diene, byfree radical initiation is the emulsion system. Polymers ranging all theway from liquid, low molecular weight (molecular weights of about 2,000to 10,000 to polymers of intermediate molecular weight (60,000 to 70,000and higher), to oil extendable, at least 50 percent soluble, rubberysolid, high molecular weight (100,000 to 500,000 or more) and evenhighly gelled, less than 50 percent soluble, may be prepared by emulsionpolymerization. The monomeric antioxidants of the present invention canbe used in such emulsion polymerization systems to produce polymers ofthe aforementioned type.

The principles of emulsion polymerization are discussed in referencessuch as "Synthetic Rubber" by G. S. Whitby, Editor-in-Chief, John Wileyand Sons, 1954, particularly Chapter 8, and "Emulsion Polymerization" byF. A. Bovey et al, Vol. IX of "High Polymers," Interscience Publishers,Inc., 1955. Some specialized applications of these principles areindicated in U.S. Pat. Nos. such as 3,080,334; 3,222,334; 3,223,663;3,468,833 and 3,099,650.

Very effective as free radical polymerization intiators used within thepractice of the present invention when used under appropriateconditions, are compounds such as t-butyl hydroperoxide, cumenehydroperoxide, diisopropylbenzene hydroperoxide and paramenthanehydroperoxides, and even hydrogen peroxide. These compounds perform veryeffectively when used in polymerization recipes containing appropriatelevels of supporting ingredients. By "supporting ingredients" is meantthose materials often referred to as activators in emulsion, or othersystems, where required. U.S. Pat. No. 3,080,334 describes some of thesematerials at column 5, lines 20-26. Such materials can also be referredto as catalyst activators. The term "Redox Polymerization" is often usedwhere the complete initiation system includes a Redox system, i.e.,reducing agents and oxidizing agents in a proportion that yieldspolymerization initiating species. All of these initiator systems arewell known in the art.

Emulsion polymerizations are normally accomplished in the range of 5° C.to 90° C. Though the activated or "Redox" initiated systems arepreferred for low temperature polymerizations, they are very effectiveat high temperatures also, normally requiring appreciably lowerquantities of the various ingredients to obtain a desirablepolymerization rate.

The free radical sources used in the initiator systems are thosecustomarily used in free radical polymerizations, for example, organicinitiators such as azonitriles, azo-derivatives, peroxides, andhydroperoxides and inorganic initiators such as inorganic peroxycompounds. Radiation, e.g., of the ultraviolet and gamma ray type canalso be used as a free radical source. Various organic initiators aredescribed by J. Brandrup and E. H. Immergut, Polymer Handbook (JohnWiley & Sons), 1965, pages II-3 to II-51.

The polymerizable antioxidants of this invention have been polymerizedat the indicated parts per hundred monomer (PHM) to producenitrile-butadiene rubber (33/67), styrene-butadiene rubber (25/75) andhydroxylated nitrile-butadiene rubber emulsion recipes. The hydroxylatednitrile-butadiene rubber contained a 30/5/65 ratio of acryloylnitrile/2-hydroxylmethylmethacrylate/butadiene. All polymers werecoagulated and then extracted for 48 hours with methanol. Oxygenabsorption data are shown in Table I below.

                  Table I                                                         ______________________________________                                                                         Hours to                                     Example   PHM     Type Polymer   Absorb 1% O.sub.2                            ______________________________________                                         4        1.5     Hydroxylated NBR                                                                             119                                           5        1.5     Hydroxylated NBR                                                                             82- 6 1.5 Hydroxylated NBR 76                No Antioxidant                                                                          --      Hydroxylated NBR                                                                             <10                                          12        1.5     Hydroxylated NBR                                                                             169                                          13        1.5     Hydroxylated NBR                                                                             17                                           13        1.5     Hydroxylated NBR                                                                             44                                           No Antioxidant                                                                          --      Hydroxylated NBR                                                                             <10                                          12        1.5     NBR            102                                          12        3.0     NBR            107                                          No Antioxidant                                                                          --      NBR            <10                                          11        1.5     NBR            110                                          ______________________________________                                    

Other antioxidants which can be made using the processes of thisinvention were tested by oxygen absorption at 100° C. The sampleantioxidants were polymerized in nitrile rubber (NBR) andstyrene/butadiene rubber (SBR) recipes at the levels shown, based on 100parts of the polymer. The data are summarized in Table II. The polymerscontaining the antioxidant were extracted for 48 hours in methanol toremove any non-bound stabilizer. The oxygen absorptions were carried outby dissolving the extracted antioxidant-containing polymer in benzene toform a cement. The cements were poured onto aluminum foil and dried toform a thin film. The weight of each sample was determined. The aluminumfoil with the adhering rubber sample was placed in the oxygen absorptionapparatus and the time required to absorb one percent oxygen by weightwas recorded. The testing procedure is fully detailed in Industrial andEngineering Chemistry, 43, page 456 (1951) and Industrial andEngineering Chemistry, 45, page 392 (1953).

                  Table II                                                        ______________________________________                                                                       100< C.                                                                       Hours to 1% O.sub.2                            Example* Parts    Polymer**    Absorption                                     ______________________________________                                        1        1.5      NBR          110                                            2        1.5      NBR          222                                            2        1.5      SBR          500                                            3        1.5      NBR          150                                            3        1.5      SBR          431                                            4        1.5      SBR          218                                            5        1.5      NBR          184                                            6        1.5      SBR          420                                            7        1.5      SBR          123                                            8        1.0      NBR          159                                            8        1.5      SBR          11                                             9        1.0      NBR          7.3                                            10       1.0      SBR          42                                             ______________________________________                                         *1. 2-(2-hydroxy-3-tert.butyl-5-ethylbenzyl)-4-ethyl-6-tert.butyl phenyl      methacrylate                                                                  2. (3,5-ditert.butyl-4-hydroxy benzyl) phenyl methacrylate                    3. 2-(3,5-ditert.butyl-4-hydroxy benzyl)-4-methyl phenyl methacrylate         4. 2-(2-hydroxy-3-tert.butyl-5-methylbenzyl)-4-methyl-6-tert.butyl phenyl     acrylate                                                                      5. 1:1 reaction product of the material produced in Example 2 and acryloy     chloride                                                                      6. 2-(3,5-ditert.butyl-4-hydroxybenzyl)-4-methyl phenyl acrylate              7. Reaction product prepared as described in Example 3                        8. 2-(2-hydroxy-3-tert.butyl-5-methylbenzyl)-4-methyl-6-tert.butyl phenyl     methacrylate                                                                  9. 2-(2-hydroxy-3-tert.butyl-5-methyl                                         phenylthio)-4-methyl-6-tert.butylphenyl methacrylate                          10. Reaction product as described in Example 14. Expected major product i     2,6-bis-(2-hydroxy-3-tert.butyl-5-methylbenzyl)-4-methyl phenyl               methacrylate                                                                  **NBR - nitrile rubber                                                        SBR - styrene/butadiene rubber                                           

While certain representative embodiments and details have been shown forthe purpose of illustrating the invention, it will be apparent to thoseskilled in this art that various changes and modifications can be madeherein without departing from the spirit or the scope of this invention.

I claim:
 1. The reaction product of a polyphenolic compound selectedfrom the group consisting of2,6-bis-(2-hydroxy-3-tert.butyl-5-methylbenzyl)-4-methylphenol;2,2'-methylene-bis-(4-methyl-6-tert.butylphenol);2,2'-methylene-bis-(4-ethyl-6-tert.butylphenol); and2,6-bis-(2-hydroxy-3-tert.butyl-5-ethyl benzyl)-4-ethylphenol, with anester forming compound of the general formula ##STR3## wherein R³ isselected from the group consisting of hydrogen and alkyl radicals havingfrom 1 to 4 carbon atoms, R⁴ is selected from the group consisting ofhydrogen and alkyl radicals having from 1 to 4 carbon atoms, and whereinA is selected from the group consisting of chlorine, iodine and bromine.2. The reaction product as described in claim 1 wherein the esterforming compound is selected from the group consisting of acryloylchloride and methacryloyl chloride.
 3. A reaction product as recited inclaim 2 selected from the group consisting of2-(2-hydroxy-3-t.-butyl-5-ethylbenzyl)-4-ethyl-6-t.-butylphenylmethacrylate;2-(2-hydroxy-3-t.butyl-5-methylbenzyl)-4-methyl-6-t.butylphenylmethacrylate;2,6-bis-(2-hydroxy-3-t.butyl-5-methylbenzyl)-4-methylphenylmethacrylate; and2-(2-hydroxy-3-t.butyl-5-methylbenzyl)-4-methyl-6-t.butylphenylacrylate.